Window envelope

ABSTRACT

The invention relates to a window envelope ( 1 ) having two flat sides, which form the front and rear sides ( 2, 3 ) thereof and are joined to each other at the edges thereof. Said window envelope also comprises an address window ( 5 ), which is made of a transparent material and which is distant from the window envelope ( 1 ) edges. Said window envelope is characterized in that the material of the address window ( 5 ) is extended to one of said edges and continues at least partially on the rear side of said window envelope ( 1 ) in a coincident manner.

[0001] The invention concerns a window envelope having two flat sides forming its front and rear sides, and having an address window made of transparent material, the address window being at a distance from the edges of the window envelope.

[0002] Envelopes are usually flat, pocket-shaped structures having two flat sides of rectangular or square outline that form the front and rear sides and are joined to one another at their edges via a fold. In the case of larger envelopes for transporting thicker sheet material (also called shipping envelopes), the edges are joined by way of spacer strips that are also foldable. The window envelope is open at one of the edges; located there is a closure flap, joined to the front side via a fold, with which the opening can be closed by folding the closure flap over onto the rear side and adhesively bonding it thereto.

[0003] Window envelopes are usually made of opaque paper material, cardboard, or plastic fiber material. They are equipped with a transparent address window on the front side. The address window is limited to the address region of a letter, and is at a considerable distance from the edges. It therefore allows only the address entered into the address field of the envelope to be seen.

[0004] U.S. Pat. No. 1,387,717 A discloses an envelope for receiving registration cards that contain information about hotel guests. To allow the information, in particular the guests' names, to be perceived without removal from the envelope, provision is made for the envelope to be cut out in the two lower edge regions so that the information written on the upper edge of the registration card is visible. The cutouts can be covered with transparent material. The cutout therefore has a function similar to that of an address window in the context of a window envelope of the kind cited initially.

[0005] DE 1 791 075 U discloses an envelope that is embodied in partly or completely transparent fashion in order to make stamps, received in the envelope, visible from the outside. If the front side is transparent, an address label is adhesively bonded onto the transparent film. This is therefore not a window envelope in which the address field is transparent so that the address written on the inserted letter is visible from outside. Instead, the address must be additionally indicated on the address label.

[0006] Very recently, terrorist activities have become known which involve the sending of biological contaminants in powdered form, for example anthrax germs, in anonymous letters. Upon contact with the powder, whether as a result of leaks in the envelope or upon opening it, persons handling such letters become infected, and often become dangerously ill. Deaths have also already occurred. With the known window envelopes, there is practically no possibility of reliably detecting whether an envelope contains such a powder.

[0007] It is the object of the invention to configure a window envelope so that it is possible to detect whether it contains powdered substances.

[0008] This object is achieved, according to the present invention, in that the material of the address window is extended to one of the edges and continues on the rear side of the window envelope at least partially congruently. The basic idea of the invention is thus to extend the transparent address window, which is present in any case, in at least one direction in such a way that one edge region is transparent. It is thus possible to detect even powder whose color does not contrast with the opaque regions of the flat sides of the window envelope. It is particularly advantageous in this context that production of such a window envelope does not entail additional manufacturing complexity, i.e. that the cost is no greater than in the case of a normal window envelope.

[0009] It is further provided according to the invention that, at least where the one flat side is transparent and the other flat side opaque, the other flat side bears a pattern on the inside. The contrast between powder and flat side, and thus the detectability of the powder, are thereby substantially improved.

[0010] The transparent regions of the envelope can be made of a transparent film or a transparent paper; the transparency must be such that a powder contained in the envelope becomes detectable.

[0011] The invention is illustrated in more detail, with reference to an exemplary embodiment, in the drawings, in which:

[0012]FIG. 1 shows the front side of a window envelope; and

[0013]FIG. 2 shows the rear side of the window envelope according to FIG. 1.

[0014] The Figures show a window envelope 1 of ordinary format having a front side 2 and a rear side 3 made of paper. Front side 2 comprises a symmetrically arranged rectangular field 4 that is made of a transparent film. It extends from the lower edge to the height of the upper edge of an address window 5 (depicted with dashed lines) that is normally present, i.e. it encloses address window 5.

[0015] It is evident from FIG. 2 that field 4 continues on rear side 3 as field 6 and is also made of transparent material, specifically in the same embodiment and arrangement as on front side 2. Fields 4, 6 are thus congruent, so that window envelope 1 is transparent in this region. It is understood that the possibility exists of reducing field 6 with respect to field 4, so that field 6 is only partially congruent with field 4. Fields 4 and 6 can also be reduced in width to the width of address field 5. 

1. A window envelope (1) having two flat sides, joined to one another at their edges and forming its front and rear sides (2, 3), and having an address window (5) made of transparent material, and having an address window (5) made of transparent material, the address window (5) being at a distance from the edges of the window envelope (1), wherein the material of the address window (5) is extended to one of the edges and continues on the rear side of the window envelope (1) at least partially congruently.
 2. The window envelope as defined in claim 1, wherein at least where the one flat side is transparent and the other flat side opaque, the other flat side bears a pattern on the inside. 